Torque Unit Converter (Nm, ft-lb & in-lb)

Torque Unit Converter (Nm, ft-lb & in-lb)

Convert torque instantly between Newton meters (Nm), foot-pounds (ft-lb), inch-pounds (in-lb), and kgf-m with bolt tightening, leverage, and engine RPM charts.

Presets label

Title control deck

= 100 Unit nm
Section fastener specsBadge iso898
Lbl friction k0.15
Section wrench geometryBadge asme b107
Kpi primary torque100 N-m= 100 Unit nm
Kpi converted torque73.76 ft-lbBadge exact iso
Kpi clamping force55.6 Unit kn12,489 Unit lbf
Kpi indicated setting100 N-m1x Badge ratio
Visual bar title
Unit nm100 N·m
Unit ft lb73.7562 ft·lb
Inch-pound (lbf·in)885.0746 in·lb
Kilogram-force meter10.1972 kgf·m
9 Units count label
Th unit nameTh symbolTh standard valueTh action
Unit nmN·m100
Unit ft lbft·lb73.7562
Inch-pound (lbf·in)in·lb885.0746
Kilogram-force meterkgf·m10.1972
Kilogram-force centimeterkgf·cm1,019.7162
Ounce-force inchoz·in14,161.1933
Kilonewton-meterkN·m0.1
Centinewton-metercN·m10,000
Dyne-centimeterdyn·cm1,000,000,000
Stat1 title100 Unit nmStat1 desc
Stat2 title55.56 Unit knStat2 desc
Stat3 title1xStat3 desc

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Technical Reference & Architecture Guide

Torque Unit Converter (Nm, ft-lb & in-lb) Guide

Convert torque instantly between Newton meters (Nm), foot-pounds (ft-lb), inch-pounds (in-lb), and kgf-m with bolt tightening, leverage, and engine RPM charts.

Torque Unit Converter (Nm, ft-lb & in-lb) Guide — Client-Side In-Memory Architecture & Data Flow
Torque Unit Converter (Nm, ft-lb & in-lb) Guide — Client-Side In-Memory Architecture & Data Flow

Key Parameters & Controls

Applied Moment (Torque Magnitude)Rotational Energy Equivalent

The rotational force applied around a fixed pivot axis, governed by ISO 80000-4. Calculated as the cross product of lever radius and perpendicular applied force vector.

Default: 100 N·m
Effective Lever Radius (Wrench Length)Linear Moment Arm

Distance from the center of the drive square to the center of the operator hand grip, calibrated under ASME B107.300 standards to ensure true manual leverage balance.

Default: 450 mm
Adapter Offset Distance (Extension)Extension Moment Arm

Centerline-to-centerline distance between the torque wrench drive square and the fastener socket center when using crowfoot or dogbone adapter attachments.

Default: 50 mm
Nut Factor (Friction Coefficient K)Dimensionless Tribological Coefficient

Empirical factor in VDI 2230 formula T = K * D * F accounting for combined thread friction and bearing surface collar friction (0.10 lubricated, 0.15 light oil, 0.20 dry zinc).

Default: 0.15
Nominal Bolt Shank Diameter (D)Fastener Geometry

Major outer thread diameter defined by ISO 261 or ASME B1.1 used to calculate stress area and ultimate tensile clamping force limits under proof load.

Default: 12 mm (M12)

Pro Tips & Best Practices

Crowfoot 90-Degree Neutral Lever Rule

Positioning a crowfoot adapter exactly 90 degrees relative to the torque wrench body maintains an effective moment arm equal to the wrench length (cos(90°) = 0). This allows you to apply the exact dial torque to the fastener without mathematical calculation or scale derating.

Spring Relaxation Storage Protocol (ISO 6789)

Mechanical click-type torque wrenches must be wound down to their lowest calibrated scale marking (typically 20% of maximum or nominal zero, never fully unscrewed below minimum) prior to storage. Leaving internal coil springs compressed induces permanent micro-strain and calibration drift beyond the allowable ±4% limit.

Lubricant Induced Bolt Yield Hazard

Applying copper anti-seize or motor oil to a bolt specified for dry torque reduces the nut friction factor K from 0.20 to approximately 0.11. Tightening to the dry torque specification will increase axial clamping force by over 80%, stretching the fastener beyond its elastic yield strength and shearing the bolt head.

Torque (N·m) Versus Work Energy (Joules) Distinction

Although both Newton-meters and Joules share the dimensional units kg·m²/s², torque is a vector cross product (force perpendicular to distance, representing rotational moment without displacement), whereas Joules represent scalar work (force dot product parallel to linear displacement). Never express torque in Joules or calories.

Common Gotchas & Troubleshooting

⚠️Fastener threads strip or bolt head snaps off before reaching specified click-type torque wrench setting

Verify whether torque specification was rated dry or wet. If threads or washers were oiled without adjusting the torque target downward by 25% to 40% (using T_wet = T_dry * (K_wet / K_dry)), clamping tension will exceed fastener ultimate tensile capacity. Also inspect thread pitch to ensure metric and imperial standard threads were not cross-threaded.

⚠️Torque wrench does not click or delivers inconsistent readings on low-torque carbon or aluminum joints

Ensure you are operating within the wrench's certified 20% to 100% calibration band. Click mechanisms below 20% of maximum scale suffer from spring hysteresis and inadequate detent breakaway energy. For low-torque settings under 10 N·m (88 in·lb), use a dedicated 1/4-inch drive micro-torque or deflection-beam wrench.

Frequently Asked Questions

How do you convert Newton-meters to foot-pounds and what is the exact formula?▼

To convert Newton-meters (N·m) to foot-pounds (ft·lb), multiply the N·m value by 0.737562149 (or divide by 1.355817948). For example, 100 N·m equals exactly 73.76 ft·lb. Conversely, to convert foot-pounds to Newton-meters, multiply ft·lb by 1.355817948.

How do you calculate the correct torque wrench setting when using a crowfoot extension?▼

When using an inline crowfoot or dogbone adapter that extends the length of the wrench, use the standard ASME formula: Wrench Setting = Target Torque * [L / (L + E)], where L is the distance from the wrench drive square to the center of the handle grip, and E is the center-to-center offset length of the extension. For example, to achieve 100 N·m on a 400mm wrench with a 50mm inline extension, set the wrench dial to 88.89 N·m.

What is the difference between foot-pounds (ft-lb) and inch-pounds (in-lb)?▼

One foot-pound equals exactly 12 inch-pounds (1 ft·lb = 12 in·lb; 1 in·lb = 0.08333 ft·lb). Foot-pounds are used for high-torque mechanical assemblies like automotive lug nuts (80-140 ft·lb) and suspension bolts, whereas inch-pounds measure low-torque precision fasteners like transmission valve bodies, valve covers, and bicycle stems (typically 30-150 in·lb) where a full foot-pound is too coarse.

Why does adding oil or anti-seize cause bolts to break at factory torque specs?▼

Torque does not directly clamp a joint; it overcomes friction. In a dry assembly, roughly 90% of applied torque is lost to thread and collar friction, with only 10% creating axial clamping tension. Adding lubricant lowers the friction coefficient (K-factor) from 0.20 to 0.10-0.12, diverting up to 25% of torque into clamping tension. This generates up to 1.8x the anticipated bolt stretch, easily exceeding the fastener yield point.

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